Question

What is the heat of formation of water vapor?

Answer 1

If you look in the back of your textbook (the appendices), you should find that it is `DeltaH_f^@ = -"241.8 kJ/mol"`. Make sure you look for `"H"_2"O"(g)` under oxygen-based substances, not `"H"_2"O"(l)`.

The formation reaction is just:

`"H"_2(g) + 1/2"O"_2(g) -> "H"_2"O"(g)`